Bradykinin binding to B2 kinin receptors and stimulation of phosphoinositide turnover and arachidonic acid release in primary cultures of cells from late pregnant rat myometrium

1992 ◽  
Vol 70 (10) ◽  
pp. 1360-1371 ◽  
Author(s):  
Margaret M. Tropea ◽  
Consuelo M. Munoz ◽  
L. M. Fredrik Leeb-Lundberg
Keyword(s):  
Arachidonic Acid ◽  
Cell Surface ◽  
Receptor Binding ◽  
Primary Cultures ◽  
Time Dependent ◽  
Pregnant Rat ◽  
Myometrial Cells ◽  
Kinin Receptors ◽  
H 20 ◽  
Stimulation Of

Primary cultures of cells from late pregnant rat myometrium contain B2 kinin receptors through which bradykinin (BK) stimulates inositol phosphate (InsP) formation and arachidonic acid (20:4) release. Equilibrium binding at 4 °C revealed that [3H]BK identified a maximal number of cell surface B2 kinin receptor binding sites on rat myometrial cells of 308 ± 78 fmol/106 cells with apparently a single equilibrium dissociation constant of 1.8 ± 0.2 nM. At 37 °C, [3H]BK binding was associated with a time-dependent decrease in the reversibility of the binding. This decrease was due in part to formation of slowly dissociating cell surface receptor [3H]BK binding and in part to internalization of the receptor-bound [3H]BK. Exposure of labeled cells to BK resulted in dose-dependent increases in [3H]InsP3, [3H]InsP2 ([3H]Ins(1,4)P2), and [3H]InsP1 [([3H]Ins(1)P1) formation and [3H]20:4 release. Pretreatment with 100 ng/mL pertussis toxin did not perturb BK stimulation of [3H]InsP formation but partially (~30%) inhibited BK stimulation of [3H]20:4 release. BK stimulation of [3H]20:4 release was directly proportional to the number of receptor sites occupied by BK. In contrast, stimulation of [3H]InsP formation required a threshold level of receptor occupancy, which decreased as a function of time of BK exposure. These results show that BK interacts with B2 kinin receptors on rat myometrial cells with apparently a single affinity through which BK stimulates [3H]InsP formation and [3H]20:4 release. BK stimulation of [3H]InsP formation requires a threshold BK concentration, which decreases with time, and we suggest that the decrease is due to a time-dependent formation of a BK receptor binding state from which BK slowly dissociates.Key words: bradykinin, receptors, myometrium, inositol phosphates, arachidonic acid.

EVIDENCE FOR A POSSIBLE FOETAL CONTROL OF PROSTAGLANDIN RELEASE FROM THE PREGNANT RAT UTERUS IN VITRO

1975 ◽  
Vol 65 (3) ◽  
pp. 429-437 ◽  
Author(s):  
M. J. PARNHAM ◽  
J. M. SNEDDON ◽  
K. I. WILLIAMS
Keyword(s):  
Arachidonic Acid ◽  
Uterine Horn ◽  
Rat Uterus ◽  
Pregnant Rat ◽  
Uterine Activity ◽  
Prostaglandin Release ◽  
Prostaglandin F ◽  
Spontaneous Contractions ◽  
Stimulation Of

SUMMARY The release of prostaglandin-like material and the spontaneous contractions of individual horns from the pregnant rat uterus in vitro have been studied on day 22 of pregnancy – the expected day of delivery. Removal of foetuses (retaining placentae in utero) from one or both uterine horns on day 16 or 17 significantly reduced prostaglandin F release and spontaneous activity. Rats which had been made unilaterally pregnant after ligation of one uterine horn, exhibited a decrease in prostaglandin F output from both horns. Uterine activity and prostaglandin release were increased in quiescent uteri by the addition of arachidonic acid (5 μg/ml) or phospholipase A (160 mu./ml); these effects were abolished by indomethacin (20 μg/ml). However, the stimulation of uterine activity by PGF2α (30–60 ng/ml) was not affected by indomethacin. It is concluded that the release of prostaglandins from the pregnant rat uterus in vitro at term is related to the presence of viable foetuses.

Potential role for mast cell tryptase in recruitment of inflammatory cells to endothelium

2005 ◽  
Vol 289 (6) ◽  
pp. C1485-C1491 ◽  
Author(s):  
Maureen C. Meyer ◽  
Michael H. Creer ◽  
Jane McHowat
Keyword(s):  
Mast Cell ◽  
Arachidonic Acid ◽  
Endothelial Cell ◽  
Cell Surface ◽  
Vascular Injury ◽  
Arachidonic Acid Release ◽  
Mast Cell Tryptase ◽  
Neutrophil Adherence ◽  
Acid Release ◽  
Stimulation Of

Recent research suggests that activation of protease-activated receptors (PARs) on the surface of endothelial and epithelial cells may play a role in general mechanisms of inflammation. We hypothesized that mast cell tryptase activation of endothelial cell PAR-2 is coupled to increased calcium-independent PLA2(iPLA2) activity and increased platelet-activating factor (PAF) production that may play a role in inflammatory cell recruitment at sites of vascular injury. Stimulation of human coronary artery endothelial cells (HCAEC) with 20 ng/ml tryptase increased iPLA2activity, arachidonic acid release, and PAF production. These tryptase-stimulated responses were inhibited by pretreatment with the iPLA2-selective inhibitor bromoenol lactone (BEL; 5 μM, 10 min). Similar patterns of increased iPLA2activity and PAF production were also seen when HCAEC were treated with SLIGKV, which represents the tethered ligand sequence for the human PAR-2 once the receptor is cleaved by tryptase. Tryptase stimulation also increased cell surface expression of P-selectin, decreased electrical resistance, and increased neutrophil adherence to the endothelial cell monolayer. The tryptase-stimulated increases in both cell surface P-selectin expression and neutrophil adhesion were also inhibited with BEL pretreatment. We conclude that tryptase stimulation of HCAEC contributes importantly to early inflammatory events after vascular injury by activation of iPLA2, leading to arachidonic acid release, PAF production, cell surface P-selectin expression, and increased neutrophil adherence.

Stimulation of arachidonic acid metabolism in primary cultures of osteoblast-like cells by hormones and drugs

1984 ◽  
Vol 28 (6) ◽  
pp. 769-781 ◽  
Author(s):  
Jean H.M. Feyen ◽  
Gertjan van der Wilt ◽  
Peter Moonen ◽  
Alfredo Di Bon ◽  
Peter J. Nijweide
Keyword(s):  
Arachidonic Acid ◽  
Acid Metabolism ◽  
Primary Cultures ◽  
Arachidonic Acid Metabolism ◽  
Stimulation Of

scholarly journals Stimulation of phosphoinositide hydrolysis by oxytocin and the mechanism by which oxytocin controls prostaglandin synthesis in the ovine endometrium

1986 ◽  
Vol 237 (3) ◽  
pp. 797-805 ◽  
Author(s):  
A P F Flint ◽  
W M F Leat ◽  
E L Sheldrick ◽  
H J Stewart
Keyword(s):  
Arachidonic Acid ◽  
Time Course ◽  
Inositol Phosphates ◽  
Fold Increase ◽  
Prostaglandin Synthesis ◽  
Time Dependent ◽  
Phosphoinositide Hydrolysis ◽  
Hydrolysis Of ◽  
Stimulation Of

Slices of caruncular endometrium from steroid-treated ovariectomized sheep were incubated with myo-[2-3H]inositol to label tissue phosphatidylinositol. Effects of oxytocin were determined on the rate of incorporation of radioactivity into phosphatidylinositol and on the hydrolysis of phosphoinositides to inositol phosphates and diacylglycerol. Incorporation of radioactivity into phosphatidylinositol was linear during 2 h incubations; 10(-7) M (100 nM)-oxytocin caused a 2.8-fold increase in the rate of incorporation. In the presence of Li+, addition of 10(-7) M-oxytocin to slices in which phosphatidylinositol was pre-labelled caused mean increase of 40-fold in the incorporation of radioactivity into inositol mono-, bis- and tris-phosphates. Inositol 1,3,4-trisphosphate was quantitatively the major trisphosphate formed. The action of oxytocin on phosphoinositide hydrolysis was dose- and time-dependent, occurring at concentrations within the range observed in plasma during episodes of secretion in vivo, and with a time course comparable with that of the action of oxytocin on uterine prostaglandin production. The effect of oxytocin on incorporation of radioactivity into inositol phosphates was not affected by inhibitors of prostaglandin synthesis. Diacylglycerol 1- and 2-lipases in caruncular endometrium converted up to 72% of added 2-[3H]arachidonyldiacylglycerol into [3H]arachidonic acid during 30 min incubations at pH 7.0. Caruncular endometrium contained 1.49 mumol of phosphatidylinositol/g, representing approx. 0.2 mumol/g of phosphatidylinositol arachidonic acid. It is proposed that the stimulation of endometrial prostaglandin synthesis by oxytocin is accounted for by increased hydrolysis of phosphoinositides to diacylglycerol and inositol phosphates with subsequent release of arachidonic acid from diacylglycerol.

Distension of the uterus induces HspB1 expression in rat uterine smooth muscle

2011 ◽  
Vol 301 (5) ◽  
pp. R1418-R1426 ◽  
Author(s):  
B. G. White ◽  
D. J. MacPhee
Keyword(s):  
Protein Expression ◽  
Stress Protein ◽  
Late Pregnancy ◽  
Cytoplasmic Localization ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Myometrial Cells ◽  
Uterine Smooth Muscle ◽  
Stimulation Of

The uterine musculature, or myometrium, demonstrates tremendous plasticity during pregnancy under the influences of the endocrine environment and mechanical stresses. Expression of the small stress protein heat shock protein B1 (HspB1) has been reported to increase dramatically during late pregnancy, a period marked by myometrial hypertrophy caused by fetal growth-induced uterine distension. Thus, using unilaterally pregnant rat models and ovariectomized nonpregnant rats with uteri containing laminaria tents to induce uterine distension, we examined the effect of uterine distension on myometrial HspB1 expression. In unilaterally pregnant rats, HspB1 mRNA and Ser15-phosphorylated HspB1 (pSer15 HspB1) protein expression were significantly elevated in distended gravid uterine horns at days 19 and 23 (labor) of gestation compared with nongravid horns. Similarly, pSer15 HspB1 protein in situ was only readily detectable in the distended horns compared with the nongravid horns at days 19 and 23; however, pSer15 HspB1 was primarily detectable in situ at day 19 in membrane-associated regions, while it had primarily a cytoplasmic localization in myometrial cells at day 23. HspB1 mRNA and pSer15 HspB1 protein expression were also markedly increased in ovariectomized nonpregnant rat myometrium distended for 24 h with laminaria tents compared with empty horns. Therefore, uterine distension plays a major role in the stimulation of myometrial HspB1 expression, and increased expression of this small stress protein could be a mechanoadaptive response to the increasing uterine distension that occurs during pregnancy.

scholarly journals Acetylcholine Receptor Stimulation Activates Protein Kinase C Mediated Internalization of the Dopamine Transporter

2021 ◽  
Vol 15 ◽  
Author(s):  
Suzanne M. Underhill ◽  
Susan G. Amara
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Surface ◽  
Dopamine Transporter ◽  
Muscarinic Receptor ◽  
Primary Cultures ◽  
Dopamine Neurons ◽  
Receptor Stimulation ◽  
Kinase C ◽  
Stimulation Of

The dopamine transporter (DAT) clears neurotransmitters from the extracellular space and serves as an important regulator of signal amplitude and duration at sites of dopamine release. Several different intracellular signaling pathways have been observed to modulate DAT activity through the regulation of the trafficking of the carriers to and from the cell surface. Acute activation of protein kinase C (PKC) by phorbol esters facilitates clathrin-dependent internalization of the DAT in a variety of model systems; however, the physiological stimuli and cell-surface receptor systems that activate PKC and regulate the DAT in dopamine neurons remain elusive. We report here that stimulation of M1/M5 muscarinic receptors in midbrain cultures decreases the ability of dopamine neurons to transport dopamine through DAT. Application of the cholinomimetic drug carbachol leads to a decrease in DAT activity in primary cultures while the M1/M5-specific antagonist, pirenzepine, blocks these effects. The M3 antagonist, DAU 5884, does not affect, but a positive modulator of M5, VU 0238429, enhances the loss of DAT function in response to carbachol and acetylcholine. These data implicate M1/M5 receptors on dopamine neurons in the modulation of DAT function. Bisindolylmaleimide, a PKC inhibitor, blocks the effects of carbachol stimulation on dopamine uptake, supporting a role for PKC in muscarinic receptor-mediated DAT internalization. Furthermore, as shown previously for PKC-induced internalization, downregulation of the DAT is dependent on both clathrin and dynamin. A Gq-specific inhibitor peptide also blocks the effects of carbachol on DAT in primary cultures, confirming Gq as the G-protein that couples M1/M5 receptors to PKC activation in these cells. In acute midbrain slices, biotinylation of cell-surface proteins revealed the loss of dopamine transport mediated by muscarinic receptor stimulation was, indeed, due to loss of membrane expression of the DAT in endogenous tissue. These data indicate that stimulation of cholinergic pathways can lead to modulation of dopamine through internalization of the DAT.

Stimulated Platelet Aggregation, Thromboxane B2 Formation and Platelet Sensitivity to Prostacyclin - A Critical Evaluation

1981 ◽  
Vol 45 (03) ◽  
pp. 204-207 ◽  
Author(s):  
Wolfgang Siess ◽  
Peter Roth ◽  
Peter C Weber
Keyword(s):  
Arachidonic Acid ◽  
Platelet Count ◽  
Platelet Aggregation ◽  
Reliable Method ◽  
Platelet Rich Plasma ◽  
Critical Evaluation ◽  
Vascular Diseases ◽  
Thromboxane B2 ◽  
Test Time ◽  
Stimulation Of

SummaryPlatelets have been implicated in the development of atherosclerotic and thrombotic vascular diseases. Evaluation of platelet aggregation in relation to endogenously formed compounds which affect platelet function may provide information of clinical and pharmacological relevance. We describe a method in which thromboxane B2 (TXB2) formation was analyzed following stimulation of platelet-rich plasma (PRP) with ADP, 1-epinephrine, collagen, and arachidonic acid. In addition, we determined platelet sensitivity to prostacyclin following ADP- and collagen-induced platelet aggregation. The parameters under study were found to depend on the platelet count in PRP, on the type and dose of the aggregating agent used, and on the test time after blood sampling. By standardization of these variables, a reliable method was established which can be used in clinical and pharmacological trials.

Sign in / Sign up

Export Citation Format

Share Document